過去完成時

1 、過去完成時是一個相對時態(tài)，表示過去的過去，只有在兩個過去發(fā)生的動作相比較時才可顯示出來。

e.g. As soon as we got to the station, the train had left.

注：主從句表達(dá)的動作緊接時，即兩動作發(fā)生的時間沒有明顯時間上的懸殊或空檔時，主從句都可用一般過去時。

e.g. Where did your brother study before he joined the army?

2 、過去完成時可表示截止過去某一時間動作的總或動作的結(jié)束。

e.g. By the end of last month. We had reviewed four books

By eight o`clock, he had finished his homework.

與這個時態(tài)連用的時間狀語常有：

by 1985, by eight o`clock, by then, by the end of last month, by the time when, when, as soon as, before 

等連詞引導(dǎo)的時間狀語從句，表示主句動作結(jié)束的時間。